Merge #11511: [Init] Remove redundant exit(EXIT_FAILURE) instances and replace with...

Merge #11511: [Init] Remove redundant exit(EXIT_FAILURE) instances and replace with return false

b296bf1 Init: Remove redundant exit(EXIT_FAILURE) instances and replace with return false (donaloconnor)

Pull request description:

  While reviewing the bitcoin code I noticed that there are a few exit(EXIT_FAILURE) at various places in the AppInit function.

  This function returns to main() which will return/exit with EXIT_FAILURE so returning false instead of an explicit exit(EXIT_FAILURE) seems to be cleaner.

  This PR attempts to make things a bit more consistent.

  There is a subtle difference between exit() and return from main in that the exit() will not clean up any local vars but I don't think this makes a difference in this case. Using exit() might even lead to bugs in the future where the dtor of local objects are expected to be called.

Tree-SHA512: 7d104c3a752b4e7d7bc2382ef7e62543462988f1bbf13dd4077fbeff5399729b76c71a4352556f188b8d306604232477466f5bb827b58a6f3f6273f2370e1faa